The objective of this research project is to obtain sufficient sequence data on the sugar binding proteins from the periplasmic space of gram negative bacteria to allow a detailed structure-function analysis of these proteins. This involves the determination of the primary structures of E. coli galactose binding protein and the determination of the changes in sequence of a number of functionally defective mutants of arabinose binding protein. Partial or total sequence analysis will also be performed on ribose binding protein. This information, together with the sequence and x-ray structure of arabinose binding protein already completed, should lead to an understanding of how these molecules interact with the membrane-bound constituents of these transport systems and facilitate transport of the sugars.